This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 21 |
| 5 | 54 |
| 6 | 167 |
| 7 | 491 |
| 8 | 1586 |
| 9 | 5132 |
| 10 | 17442 |
| 11 | 60399 |
| 12 | 216172 |
| 13 | 790436 |
| 14 | 2965333 |
| 15 | 11365813 |
| 16 | 44536775 |
| 17 | 178107679 |
| 18 | 726716229 |
| 19 | 3022464373 |
| 20 | 12807206008 |
| 21 | 55253891494 |
| 22 | 242585471236 |
| 23 | 1083255591604 |
| 24 | 4917631017573 |
| 25 | 22685090928596 |
| 26 | 106291554085987 |
| 27 | 505653658171936 |
| 28 | 2441383079595849 |